package edu.zzuli.util;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Map;

import org.springframework.core.CollectionFactory;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.JdbcUtils;

public class MyColumnMapRowMapper implements RowMapper {
	private static RowMapper rowMapper;

	private MyColumnMapRowMapper() {
	}

	public static RowMapper newInstance() {
		if (rowMapper == null) {
			rowMapper = new MyColumnMapRowMapper();
		}
		return rowMapper;
	}

	public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
		ResultSetMetaData rsmd = rs.getMetaData();
		int columnCount = rsmd.getColumnCount();
		Map mapOfColValues = createColumnMap(columnCount);
		for (int i = 1; i <= columnCount; i++) {
			String key = getColumnKey(rsmd.getColumnName(i));
			Object obj = getColumnValue(rs, i);
			mapOfColValues.put(key, obj);
		}
		return mapOfColValues;
	}

	/**
	 * Create a Map instance to be used as column map.
	 * <p>
	 * By default, a linked case-insensitive Map will be created if possible,
	 * else a plain HashMap (see Spring's CollectionFactory).
	 * 
	 * @param columnCount
	 *            the column count, to be used as initial capacity for the Map
	 * @return the new Map instance
	 * @see org.springframework.core.CollectionFactory#createLinkedCaseInsensitiveMapIfPossible
	 */
	@SuppressWarnings("deprecation")
	protected Map createColumnMap(int columnCount) {
		return new TMap(CollectionFactory.createLinkedCaseInsensitiveMapIfPossible(columnCount));
	}

	/**
	 * Determine the key to use for the given column in the column Map.
	 * 
	 * @param columnName
	 *            the column name as returned by the ResultSet
	 * @return the column key to use
	 * @see java.sql.ResultSetMetaData#getColumnName
	 */
	protected String getColumnKey(String columnName) {
		return columnName;
	}

	/**
	 * Retrieve a JDBC object value for the specified column.
	 * <p>
	 * The default implementation uses the <code>getObject</code> method.
	 * Additionally, this implementation includes a "hack" to get around Oracle
	 * returning a non standard object for their TIMESTAMP datatype.
	 * 
	 * @param rs
	 *            is the ResultSet holding the data
	 * @param index
	 *            is the column index
	 * @return the Object returned
	 * @see org.springframework.jdbc.support.JdbcUtils#getResultSetValue
	 */
	protected Object getColumnValue(ResultSet rs, int index) throws SQLException {
		return JdbcUtils.getResultSetValue(rs, index);
	}

}